There's nothing like the feeling of writing. Letting out the creativity that's in your brain, putting it on paper (or the virtual paper of a Word doc) and honing it to perfection. Scenes are written, critiqued, and rewritten. Verbs are made stronger. Words are added to engage all the senses. You have a masterpiece on your hands.
With the confidence that can only come from naiveté, you hand it over to an editor for "a quick proof."
When I talk to people before doing an evaluation, I've found most of them believe their manuscripts only need a light edit, similar to the "quick once-over." I am sorry to report that most manuscripts need more than a passing glance. Indeed, copy editors can't afford to gloss over the manuscripts entrusted to their care. If we do our jobs properly, we read every word, multiple times.
The funny thing about reading each word is that it enables mistakes to be found. Sometimes there are a lot of them, and sometimes only a few, but even the most careful writer makes mistakes. It's just the way it goes.
In one of life's ironies, the writers who think they need the most help are rarely those who have the most errors in their manuscripts. Even so, the typical copy edit looks worse than it is, with all that red ink standing out so starkly against the black and white.
You'll just have to trust me when I say copy editors—well, most of them, anyway—don't take sadistic pleasure in marking up manuscripts. I know I don't. There's a satisfaction that comes from knowing I'm helping someone's work to look its best, but when there are a lot of corrections to be made, my feelings run more toward the nervous side. Will the author think I'm taking liberties that aren't mine to take? Will he resent my advice? Will she wonder if I really know what I'm talking about? Am I being too bossy?
Those who have worked with me know I'm a big fan of margin notes. I like to use the margin as an easy means of communication between me and the author. I can write things as I think of them, where they apply, so I don't have to save it all for an email summary. Sometimes I'll explain why I've changed something that may not have seemed incorrect; other times, I'll explain an odd rule, like the "sometimes hyphenated, sometimes not" words; other times I just want to show my appreciation for a nicely written passage or a funny exchange between characters.
When all is said and done, I hope the writer recognizes that I've made suggestions that will improve the manuscript. Seeing "all that red ink" may come as a shock, but as long as the author knows I have his or her best interests in mind, the red is just a little ol' lipstick kiss at the end of a soon-to-be-great manuscript.